title: Impact of aortic valve replacement on outcome of symptomatic patients with severe aortic stenosis with low gradient and preserved left ventricular ejection fraction.
abstract: BACKGROUND
  The optimal management of low-gradient "severe" aortic stenosis (mean gradient <40 mm Hg, indexed aortic valve area ≤0.6 cm2/m2) with preserved left ventricular ejection fraction remains controversial because gradients may be similar after aortic valve replacement (AVR). We compared outcomes of low-gradient severe aortic stenosis with AVR or medical therapy.
  
  
  RESULTS
  Comprehensive echocardiographic measurements including hemodynamic calculations were completed in 260 prospectively identified patients with symptomatic low-gradient severe aortic stenosis. Patients were followed up for mortality over 28±24 months. AVR was performed in 123 patients (47%). Compared with AVR patients, medically treated patients had a higher prevalence of diabetes mellitus (25% versus 41%, P=0.009), lower stroke volume index (36.4±8.4 versus 34.4±8.7 mL/m2, P=0.02), higher pulmonary artery pressure (38±11 versus 48±21 mm Hg, P=0.001), and higher creatinine level (1.1±0.4 versus 1.22±0.5 mg/dL, P=0.02). These and other clinically relevant variables were entered into a propensity model that reflected likelihood of referral to AVR. This score and other variables were entered into a Cox model to explore the independent effect of AVR on outcome. During follow-up, 105 patients died (40%): 32 (30%) in the AVR group and 73 (70%) in the medical treatment group. AVR (hazard ratio, 0.54; 95% confidence interval, 0.32-0.94; P<0.001) was independently associated with outcome and remained a strong predictor of survival after adjustment for propensity score. Medical therapy was associated with 2-fold greater all-cause mortality than AVR. The protective effect of AVR was similar in 125 patients with normal flow (stroke volume index >35 mL/m2; P=0.22).
  
  
  CONCLUSIONS
  AVR is associated with better survival than medical therapy in patients with symptomatic low-gradient severe AS and preserved left ventricular ejection fraction.
authors.affiliation: Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Alper
authors.initials: A
authors.lastname: Ozkan
authors.forename: Rory
authors.initials: R
authors.lastname: Hachamovitch
authors.forename: Samir R
authors.initials: SR
authors.lastname: Kapadia
authors.forename: E Murat
authors.initials: EM
authors.lastname: Tuzcu
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Marwick
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000401:mortality* / Q000503:physiopathology / Q000601:surgery*; D063126:Balloon Valvuloplasty; D003920:Diabetes Mellitus / Q000401:mortality; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: aortic stenosis; aortic valve; treatment outcome